LEDs are commonly used in lighting applications, and have in many areas superseded conventional lighting, including decorative elements, indicators etc. LEDs have various advantages: they are cost effective, easy to implement and typically consume very little power. Furthermore, LEDs may be employed to produce a lighting system with a varying color scheme, which is often desired for applications such as lamps, back light sources, traffic signals, display boards, illuminating switches and commercial lighting. LEDs provide the best option for these applications as they are easily available in basic colors Red, Green and Blue (RGB) and any other colors can be produced by manipulating the intensity of these basic colors RGB.
U.S. Patent publication number US 2004/0207334 discusses a system for a color changing bulb for the instrument panel of a vehicle, which is made as a bulb and directly installable in a bulb seat of the instrument panel. The color changing bulb includes a bulb housing defining a receiving space for receiving a light emitting diode and a circuit board. The LED includes three LED chips for generating red, blue and green light components. A controlling circuit is disposed on the circuit board and connected with the LED for driving the three-color LED chips to emit light. By use of a brightness adjustment switch on the instrument panel or a headlight switch, at least seven combinations of colors of light can variably emitted. This patent provides a memory unit to store or count the number of times the headlight switch is switched to create additional signal indicating which color the LED system should produce. This system is further using stabilizing unit and a digital cycle outputting unit, which makes it limited to only cyclic color changes and does not provide with an option for selecting a single color and the system can not be programmed for selecting flashing or steady state color mode.
In another US Patent publication, number US 2002/0047628, a system is discussed which is more complicated and requires a more complex infrastructure to control and use the system, making it both bulky and costly. This art is used in larger applications such as in decorating retail, commercial and residential places; thus limiting this system to outdoor environments. It is not cost-effective in smaller applications.
In another U.S. Pat. No. 5,420,482, a color display apparatus is disclosed in which each of the three color LED in the circuit are driven by transistor biasing. In this system, each transistor base is coupled to a respective latch resistor. As the three latches are connected to a single data bus, it becomes impossible to change the color of all the three LED's at a very high speed. Also, the biasing of the transistor was changed by simply changing the grounding resistor of the potential divider which may vary from piece to piece due to component tolerance.
U.S. Pat. No. 6,016,038 to Mueller, et al. discloses a pulse width modulated current control for an LED lighting assembly, where each current-controlled unit is uniquely addressable and capable of receiving illumination color information on a computer lighting network. The light module is adapted to be conveniently interchanged with other light modules having programmable current and hence maximum light intensity, ratings. The pulse width modulated LED lighting assembly of this invention however necessitates the use of a computer controller to operate the system.
U.S. Pat. No. 6,150,774, also to Mueller, et al. discloses a similar pulse width modulated current control for an LED lighting assembly wherein each current-controlled unit is uniquely addressable and capable of receiving illumination color information on a computer lighting network. This patent anticipates the use of a manual control for an LED lighting assembly, however there is no method for manually programming an LED light source with such a method.
U.S. Pat. No. 6,211,626 to Lys, et al. discloses a light module, comprising an LED system for generating a range of colors within a color spectrum, a processor for controlling the amount of electrical current supplied to the plurality of light emitting diodes, so that a particular amount of current supplied thereto generates a corresponding color within the color spectrum, a housing within which the LED system is positioned, and a heat spreader plate in contact with the housing for dissipating heat from the housing; wherein the LED system includes a thermal connection to the heat spreader plate. This invention fails to provide for a manual, switched color or color array setting mode.
U.S. Pat. No. 6,340,868 to Lys, et al. discloses a light module having a plurality of light emitting diodes for generating light of a range of colors within a color spectrum, a processor for controlling the amount of electrical current supplied to each light emitting diode such that a particular amount of current supplied to the light module generates a corresponding color within the color spectrum, and a power module for providing electrical current from a power source to the light module, the power module including a connector for removably and replacably connecting the power module to the light module. However, this invention contemplates a computer controlled multicolored lighting network, rather than individual lighting units which may be programmed to multiple modes in a series by a manual switch.
U.S. Pat. No. 6,528,954 to Lys, et al. also relates to LED lighting assemblies, however this patent claims the use of a processor to control current through the LEDs, rather than a technique to control pre-programmed modes through a manual switch.
U.S. Pat. No. 6,806,659 to Mueller, et al. discloses a pulse width modulated current control for an LED lighting assembly, wherein each current-controlled unit is uniquely addressable and capable of receiving illumination color information on a computer lighting network. In a further embodiment, the invention includes a binary tree network configuration of lighting units (nodes). In another embodiment, the present invention comprises a heat dissipating housing, made out of a heat-conductive material, for housing the lighting assembly. The heat dissipating housing contains two stacked circuit boards holding respectively the power module and the light module. The light module is adapted to be conveniently interchanged with other light modules having programmable current, and hence maximum light intensity, ratings. Like the other background references, this invention doesn't contemplate an LED lighting assembly, wherein the ON/OFF switch is also the color control.
The above mentioned prior art does not provide choice of selection of cyclic or steady state color modes. Although several instances of the prior art have the capability of generating a variety of combinations, they lack the ability to make color changes without large, costly, complex controllers, and are not suitable for use in small applications. Furthermore, these arts do not provide any memory means to store a mode of operation and color or color combination when they are switched off, to restore a variety of predetermined settings at the time of the next restart.